Tooth coating composition

ABSTRACT

A film forming composition for coating teeth which is a mixture of about 0.5% to about 30% by weight of a film forming polymer; about 10% to about 99.5% by weight of solvent; about 0.05% to about 40% by weight of a rheology modifier; about 0.01% to about 5% by weight of a dispersant or plasticizer, if necessary; and optionally up to about 30% by weight of an opacifier or colorant.

BACKGROUND OF THE INVENTION

The present invention is directed to a film forming coating for coatingteeth. It is a temporary coating which will eventually wear off or maybe easily removed when convenient or desired.

Temporary protective coatings or removable protective coatings areknown. For example, U.S. Pat. No. 5,191,014, to Roberts et al., teachesa temporary protective aqueous coating composition which is applied tothe hydrophobic paint work of newly finished motor vehicles, and yet iseasily removable. The composition is a copolymer of (meth)acrylic acid,and a staple monomer, which creates a copolymer coating having amolecular weight of 10,000 to 200,000 that is soluble under alkalineconditions. U.S. Pat. No. 5,330,788, to Roberts, teaches a temporarycoating to protect the surface of an article, which coating is weatherresistant but soluble under alkaline conditions and which is afilm-forming acrylic polymer. U.S. Pat. No. 5,916,674, to Skelly, etal., discloses an article having a removable protective film to protectthe activated nature of an activated surface. The film-forming substanceis water soluble, preferably a vinylpyrrolidone and vinyl acetatepolymer. U.S. Pat. No. 5,945,462, to Salamon, discloses temporaryprotective coatings for precision surfaces such as glass, metals,ceramics, plastic and other materials of construction where the coatingis a (meth)acrylate-capped organic prepolymer resin having at least onependent hydrophilic group. This film-forming system is dependent onreactive curing of monomers and prepolymers.

There are patents which teach cosmetically improving and altering theappearance of teeth, such as U.S. Pat. No. 6,036,494, to Cohen, whichteaches the use of a Bis-GMA (compound) (bisphenoldiglycidylmethacrylate) or a glass ionomer. The coatings are reactedfrom monomers and/or prepolymers at the dental surface and can bepigmented. But once coated, it cannot be removed without using a dentalpick or tool to remove the shell coating from the tooth. U.S. Pat. No.5,980,868, to Homola, et al., discloses a dental delivery system for theprotection of surfaces of teeth. The Homola composition provides aprotective coating of fatty/waxy base which functions as a transferagent or barrier stratum, but it does not appear to be a temporaryremovable coating. U.S. Pat. No. 4,512,743, to Santucci et al., teachesa polymerizable composition which can be applied to the surface ofteeth, but it requires the etching of the tooth surface before applyingthe coating. U.S. Pat. Nos. 4,883,534, and 4,496,322, both to Sandham,et al., teach a varnish containing a dentally acceptable antimicrobialagent which can be painted on teeth to give a transparent, translucentor tooth colored film which is effectively invisible but providessustained release of the antimicrobial agent. This is a film which isused to treat infection and can be removed by the application of theliquid varnish base. U.S. Pat. No. 5,430,074, to Barnes, et al., teachesa dental restoration kit which provides a gum-colored dental compositefor restoring cavities and shorten the appearance of clinical crown onthe facial surface of a tooth. The composition is a methacylate resin.The components are presented separately in a kit for combination andapplication to the tooth. The composition is reactive and is notconsidered a temporary removable composition. U.S. Pat. No. 4,032,627,to Suchan, et al., teaches a tooth whitening cosmetic composition thatis applied temporarily and then removed with solvent. An alkalinesolution is necessary for removal. U.S. Pat. No. 4,648,845, to Orlowskiet al., teaches a method for indirect bonding of chemically or lightcurable resin-based restoratives such as acrylates and methacrylates tothe base metal of dental cast restorations. The composition of Orlowskiis not intended to be a temporary removable coating.

While the prior art coatings in general can be easily strippable, theyare not suggested for use on teeth, and the coatings that are used forteeth which are removable require special tools or compositions tosubsequently remove the coatings. The prior art coatings have beencreated from reactive monomers, prepolymers, and where necessary, highlyreactive initiators like organic peroxides and light sensitivecompounds. Any substantially reactive chemical system has the ability toaffect the normal chemistry of living tissue and produce unsafe,unwanted, and sometimes toxic and detrimental changes. Likewise, thesolvent systems described have included generally toxic compoundsincluding reactive species. The prior art coatings have also beensubject to removal or degradation by changes in acid/base balance, mostnotably toward basic conditions. Acidic and basic conditions are bothfound in day-to-day activities including eating and tooth brushing. Whenthe conditions of film removal are found in common activities, the filmis subject to premature and possibly unexpected and embarrassingremoval.

SUMMARY OF THE INVENTION

The present invention is to a temporary or removable film formingcomposition for coating teeth which is a mixture of a natural orsynthetic film forming polymer, a solvent, a rheology modifier, adispersant or plasticizer, if necessary, and optionally an opacifier orcolorant. It is applied to teeth preferably by brushing it on the toothsurface. The user can create temporary colors for the teeth or coverblemished or off color teeth. When the coating is no longer desired, itis readily stripped off. The film-forming system contained herein hasseveral advantages over the cited prior art.

The film-forming system of the present invention comprises orallyacceptable ingredients, which, individually, are described in the“Handbook of Pharmaceutical Excipients, 2^(nd) ed”. The compounds of thepresent invention are acceptable and preferred for their demonstratedsafety in pharmaceutical preparations. They also produce a film thatshows no water solubility invariant of acid/base changes and which has auseful durability as a temporary and removable film. The presentinvention is a product that gives an aesthetically pleasing coating thatis safe in its intended use, shows good performance over a plannedduration, and is easily and safely removable when desired.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a film forming composition for coating teethwhich is a mixture of a film forming polymer; a solvent; a rheologymodifier; a dispersant or plasticizer, if necessary; and optionally anopacifier or colorant.

Film formers may be any of the natural polymers including commonly usedgums, resins, exudates, animal rendering products and byproducts, suchas gelatin and keratin, plant extracts, alginates, cellulose,galactomannans, bacterial products, such as Xanthan gum, and derivativesof these natural polymers, including methyl-, hydroxypropyl-, acetatephthalate, acetate, methoxy, hydroxypropoxy, acetyl, phthalyl,hydrolysates, and salts (Li, Na, K, Ca, Mg, Al, Zn, B. Fe, Cu, Ni), orcombinations thereof or associated reaction byproducts. They may also besynthetic polymers, including homopolymers, copolymers, interpolymers,block polymers, or graft polymers, either crosslinked or substantiallylinear, derived from monomers known to film forming arts such as(meth)acrylic acid homo- and copolymers, including those to be found inU.S. Pat. Nos. 2,798,053; 3,940,351; 5,034,486; 5,034,487; 5,034,488;4,062,817; 3,940,351; 2,340,110; 2,340,111; 2,533,635; the disclosuresof which are incorporated herein by reference; and which are directedmainly at olefinically unsaturated moieties of various functionality andsubstitution. The film forming polymer is preferably an acrylic ormethacrylic, i.e., (meth)acrylic acid polymer or copolymer, includingacrylic acid, methyl acrylate, ethyl acrylate, methacrylic acid, methylmethacrylate, ethyl methacrylate, etc. A preferable acrylic polymer isavailable from Rohm Pharma GmbH as Eudragit RS 100 and it is the salt ofa copolymer of ethyl acrylate, methyl methacrylate, and trimethylammonioethylmethacrylate. Other polymers that could be used includeethylcellulose, polyvinyl acetate, aminoalkyl methacrylate copolymer,chitin, chitosan, wax-type coatings, and the like. Another film formingpolymer is Acrycoat acrylic and methacrylic polymers from CorelPharma-Chem, Ahmedabad, India. What is important is that the polymer isappropriate for use in a mouth and forms a film, has sufficientstrength, adheres, and can be subsequently removed. The film former ispresent in an amount of about 1% to about 30% by weight based upon theweight of the total mixture, although an amount of 5 to 20% by weight ispreferred, with about 10% being further preferred.

Any solvent deemed suitable for the desired application/substrate may beused. This includes considerations of cost, color, ease of application,toxicology, environmental impact, regulatory status, effect on filmformation and finished properties such as gloss, levelling, taste,flexibility, surface hardness, tensile strength, modulus, abrasionresistance, stain resistance, porosity, release/retention/absorbtion oftarget compounds, adhesion, cohesion, and ease of removal, e.g.,methanol, ethanol, isopropanol, butanol, water, methylene glycol,ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol,hexylene glycol, acetone, methyl ethyl ketone, ethyl acetate, butylacetate, cyclohexanone, cyclohexane, methylene chloride, chloroform,carbon tetrachloride, trichloroethylene, perchloroethylene, methylglycol acetate, toluene, benzene, diethyl ether, benzyl alcohol, andglycerin. The solvent is present in an amount of about 10% to about99.5% by weight based upon the total weight of the mixture, althoughabout 60% to about 90% by weight based upon the weight of the totalmixture is preferred, with an amount of 80% by weight being furtherpreferred.

The rheology modifier is selected to adjust the flow properties of themixture so that it will remain on a vertical surface without running orcreeping. The rheology modifier can be any of the known inorganicrheology modifiers such as clays, such as laponite, bentonite, and thelike, and thickener grade silicas, which are well known for use inpaints and coatings, commonly used gums, resins, exudates, animalrendering products and byproducts, such as gelatin or keratin, plantextracts, alginates, cellulose, galactomannans, bacterial products, suchas Xanthan gum, and derivatives these compositions, including methyl-,hydroxypropyl-, acetate phthalate, acetate, methoxy, hydroxypropoxy,acetyl, phthalyl, hydrolysates, or salts (Li, Na, K, Ca, Mg, Al, Zn, B,Fe, Cu, Ni), or combinations thereof. They may also be syntheticpolymeric rheology modifiers, including homopolymers, copolymers,interpolymers, block polymers, and graft polymers, either crosslinked orsubstantially linear, derived from monomers known to those skilled inrheology modification such as (meth)acrylic acid homo- and copolymers,including those to be found in U.S. Pat. Nos. 2,798,053; 3,940,351;5,034,486; 5,034,487; 5,034,488; 4,062,817; 3,940,351; 2,340,110;2,340,111; 2,533,635. A preferred rheology modifier is 2-hydroxypropylcellulose. Other rheology modifiers could include crosslinked acrylicacid polymer and copolymers, such as Carbopol polymer from Noveon Inc.and Acrypol polymers from Corel Pharma-Chem, and the S-1700-L series ofpolymers from SNP, Inc. The rheology modifier is present in an amount ofabout 0.01% to about 40% by weight based upon the weight of the totalmixture, although an amount of 1% by weight is preferred.

The dispersants may be chosen from many known in the arts concerned withparticulate dispersion, particularly pigment dispersion, wherecompatible with the desired application and/or substrate. A dispersantor plasticizer may not be necessary if the polymer allows for the mixingand dispersion of the ingredients. Usually, this is not the case, but itwill depend upon the polymer chosen. They may also be selected forreasons described in the choice of solvents above. e.g. sodium laurylsulfate, polyoxyethylene alkyl ethers, polyoxyethylene castor oilderivatives, polyoxyethylene sorbitan fatty acid esters, polyethyleneglycols (PEG), polypropylene glycols (PPG), polyethylene-polypropylenecopolymers/block polymers (PEG/PPG), unsaturated polyoxyethylene ethers,silicone copolyols, perfluoroalkyl copolyols. The dispersant is presentin an amount of about 0.01% to about 5% by weight based upon the weightof the total mixture, with an amount of 0.5% by weight being furtherpreferred.

Plasticizers can be added specifically for the purpose of film propertymodification or may be added primarily for other functions includingsolvent, dispersant, or another film former. These additives are wellknown in the plastic and film forming arts, e.g., PEG, PPG, PEG/PPG,phthatlic esters, phosphoric esters, esters of adipic, azelaic, glutavicor sebacic acid, fatty acid esters or petaerithrol and their epoxides,citric esters, esters of acetic, propionic or butyric acid, esters ofethylbutyric or ethyl hexanoic acid, glycol esters, benzoic esters,trimellitic esters, sulfonic esters, sulfonamides, anilides, alcohols,ethers, ketones, and abietic derivatives. The dispersant is present inan amount of about 0.01% to about 5% by weight based upon the weight ofthe total mixture, although an amount of 0.5% by weight is preferred.

Colorants or opacifiers may include both soluble and insoluble compoundsand their mixtures known to the arts concerned with coloring, e.g.,titanium dioxide, iron oxides and their hydrates, carbon blacks, talc,clays, dyes, lakes, gold and various pigments. The colorant or opacifieris present in an amount of about 0% (i.e., none) to about 30% by weightbased upon the weight of the total mixture, although an amount of about1 to about 10% by weight is preferred. The colorant can be such as wouldmatch the surrounding teeth or could be in a non-tooth color, such ascolors for athletic events, holidays, temporary gold teeth orglow-in-the-dark colors.

Additionally, compounds can be added specifically to promote otherdesireable qualities of the in-process product, finished product, or itsresultant film. It is also possible to realize similar qualities frommulti-functional ingredients added for other primary benefits. Suchdesireable qualities may include considerations listed in the choice ofsolvents above.

The composition of the present invention is primarily for use as a toothcoating, though it could be used as a protective barrier, a diffusionlimiting, controlled release coating, a carrier for a drug substance, alow-concentration, long-duration bleaching or surface treating agent, anantimicrobial (chlorhexidines), or some similar application.

The composition is applied by spraying, brushing, or other convenientcoating process. The process is not critical, although brushing is themost practical and is preferred. Although the application devices is notcritical, one convenient way of applying the composition would be a tubehaving a wicking device to deliver the coating to a tip which protrudesfrom the tube. The tip is then pressed against the tooth to deliver thecoating. This type of device is similar to a “magic marker”. Otherdevices include a container and brush similar to that for nail polishand the felt pads used for applying make-up.

The coating of the present invention is used as a cosmetic covering overundesirable appearing teeth. It can be applied to the surface of thetooth, but is not a permanent correction because it can be easilyremoved. It can be used to cover the surfaces of the teeth or to coverold and discolored fillings, or to cover the dark margins of crowns dueto gum recession, or to coat crowns that no longer match so that thecrown does not have to be replaced. It can also be used to cover a tooththat has a gray appearance due to root canal therapy or large amalgamfillings. The coating of the present invention does not alter the toothin any way, except the color, and it is reversible. It is designed to beaffordable because it does not require a licensed professional forbleaching, bonding, crowns, or veneers. Although not necessary, ifdesired, the surface of the tooth could be etched using a citric acidwash or a phosphoric acid (33% concentration) treatment (if doneprofessionally by a dentist) to promote greater adhesion and a longerretention time.

The following example is illustrative of the present invention, andshould not limit the scope of the invention.

EXAMPLE 1

Ingredient wt. % Function Ethanol 79.10 Solvent/Preservative Endragit RS100 10.00 Film Former/Rheology Modifier Klucel HF Pharm 00.60 RheologyModifier/Film Former Tween 80 00.30 Dispersant/Plasticizer TitaniumDioxide 10.00 Opacifier/Colorant Total: 100.00Preparation:

-   1. (optional) Freeze grind Eudragit to a powdered form to facilitate    its dissolution.-   2. Dissolve Eudragit into ethanol.-   3. Add Tween 20 to the Eudragit solution and disperse TiO2 in the    same under high shear conditions (rotor-stator, colloid mill, ball    mill, etc.). This may be done prior to step 1. where the shear    necessary is detrimental to the film former(s).-   4. Disperse Klucel into the Eudragit solution and mix at moderate    shear (marine impeller, etc.) to fully dissolve and extend the    Klucel.

Removal of the film coating may be easily and safely effected using asolution of 70% ethanol, or of similar composition as the originalcarrier solvent medium. This allows the removal of the film undercontrolled and mild conditions not likely to be found day-to-day in theoral cavity thus preventing its premature removal. The film in Example 1has endured without significant change for four days, at which time itwas easily removed in about one minute cleanly and completely with an80% solution of ethanol in water.

Description of Selected Ingredients:

Ingredient Description Source Eudragit A salt of a copolymer ofethylacrylate, Rohm Pharm GmbH RS 100 methylmethacrylate andtrimethylammonioethylmethacrylate (EA:MA:TMAEMA = 1:2:0.1); MW = 150,000Klucel 2-hydroxypropyl cellulose Aqualon HF Pharm Tween 80Polyoxyethylene sorbitan monoleate ICI

The foregoing embodiments of the present invention have been presentedfor the purposes of illustration and description. These descriptions andembodiments are not intended to be exhaustive or to limit the inventionto the precise form disclosed, and obviously many modifications andvariations are possible in light of the above disclosure. Theembodiments were chosen and described in order to best explain theprinciple of the invention and its practical applications to therebyenable others skilled in the art to best utilize the invention in itsvarious embodiments and with various modifications as are suited to theparticular use contemplated. It is intended that the invention bedefined by the following claims.

1. A film forming composition for coating teeth comprising thefollowing: A) about 0.5% to about 30% by weight, based upon the weightof the composition, of a film forming polymer, wherein the film formingpolymer is a salt of a copolymer of ethylacrylate, methylmethacrylateand trimethylammonioethylmethacrylate; B) about 10% to about 99.5% byweight, based upon the weight of the composition, of solvent; C) about0.01% to about 40% by weight, based upon the weight of the composition,of a hydroxy propyl cellulose theology modifier; and D) optionally up toabout 30% by weight, based upon the weight of the composition, of anopacifier or colorant.
 2. The composition of claim 1 wherein the filmforming polymer is selected from the group consisting of natural andsynthetic polymers.
 3. The composition of claim 1 wherein the filmforming polymer is a (meth) acrylate copolymer.
 4. The composition ofclaim 1 wherein the film forming polymer is present in an amount ofabout 1% to about 20.0% by weight.
 5. The composition of claim 1 whichfurther includes a dispersant or plasticizer.
 6. The composition ofclaim 1 which further includes a dispersant or plasticizer in an amountof about 0.01% to about 15% by weight, based upon the weight of thecomposition.
 7. The composition of claim 6 wherein the dispersant ispolyoxyethylene sorbitan monoleate.
 8. The composition of claim 6wherein the dispersant or plasticizer is present in an amount of about0.1% to about 5.0% by weight.
 9. The composition of claim 1 wherein thesolvent is ethanol.
 10. The composition of claim 1 wherein the solventis present in an amount of about 60.0% to about 80.0% by weight.
 11. Thecomposition of claim 1 wherein the rheology modifier is present in anamount of about 0.05% to about 40.0% by weight.
 12. The composition ofclaim 1 wherein the opacifier is titanium dioxide.
 13. The compositionof claim 1 wherein the opacifier or colorant is present in an amount ofabout 0.0 1% to about 30% by weight.
 14. A film forming composition forcoaling teeth comprising the following: A) about 0.5 % to about 30% byweight, based upon the weight of the composition, of a film formingpolymer; B) about 10% to about 99.5% by weight, based upon the weight ofthe composition, of solvent C) about 0.01% to about 40% by weight, basedupon the weight of the composition, of a hydroxy propyl celluloserheology modifier, D) a dispersant or plasticizer in an amount of about0.01% to about 15% by weight, based upon the weight of the composition,wherein the dispersant is polyoxyethylene sorbitan monoleate; and E)optionally up to about 30% by weight, based upon the weight of thecomposition, of an opacifier or colorant.